Liposuction is a surgical technique using instruments to remove unwanted fatty tissue in a minimally invasive fashion from humans or animals. Typically liposuction is carried out with a tumescent fluid to allow improved anesthesia and minimal blood loss. The waste fluid and fatty tissue is commonly discarded, although sometimes the adipose tissue may be reclaimed and transplanted back into the patient for aesthetic, cosmetic or other therapeutic reasons.
Adipose tissue transfer, however, has been fraught with difficulties in that loss of volume and even necrosis to the transposed fat may occur; either result yielding aesthetically unappealing results and the necessity for repetitive treatments or treatments with an alternate material or dermal filler. Successful fat transfer in the nude mouse model with human tissue has been confirmed by Kitagawa and Takamatsu when transferring adipose cells with a partially purified mixture of adult stem cells isolated from the original lipoaspirate tissue and fluid (Takamatsu 2006). Others have hypothesized that these adipose derived stem cells also carry other therapeutic uses and have devised methods of isolating them (Halvortsen 2006).
One method and system, made by the Cytori corporation, uses a series of enzymatic buffers and washing agents in combination with a modified centrifugation system to isolate the stromal vascular fraction of liposuction waste (Zuk 2001). The stromal vascular fraction is enriched with adipose stem cells in addition to other cells. This fraction may then be used for further culture, isolation and/or manipulation of pure stem cells for further cellular therapies. Although the Cytori device is able to isolate stem cells in a facile fashion, the cost of the modified centrifugation system is prohibitively expensive and is composed of moving parts which invariably will require maintenance. Furthermore the centrifugation method is not capable of directly isolating and selecting specific cells expressing antigen markers of clinical interest. Other devices such as those mentioned in U.S. Pat. Nos. 5,409,833, 5,610,074, 5,786,207 and 6,316,247 though economical are still unable to selectively remove specific subsets of cells from the entire liposuction fluid milieu. This is concerning as stem cells do have the potential of becoming any type of tissue including possibly even malignant tissue or tissue that is inappropriate for the site of transfer. For example, if adipose derived stem cells were transferred to a soft tissue area such as the lips, specific stem cells ultimately destined for bone production would lead to hardening of the intended area of treatment. Therefore, an alternate method and apparatus less costly and having greater specificity of isolating clinically relevant cells would be of both clinical and commercial relevance.